The general public and even most nuclear engineers do not understand how easy it is for nuclear fuel to fail. Since the dawn of the nuclear era, nuclear fuels have been designed and built to meet only a small portion of the full requirements. This was due to material and technology limitations as well as costs. The only economical and practical way to use nuclear material for power has been simple fuel oxide pellets in metal cans.
That is now changing with the introduction of TRISO particle based fuels and use of advanced radiation tolerant ceramics. In this post, I will explain the performance goals of nuclear fuel and then show how normal fuels compare relative to TRISO based fuels.
Still there's a limit to what I can do with words. I can write all about nuclear accidents and the performance characteristics of traditional fuel compared to new TRISO-based fuels, but people often don't get it. The technical discussion of materials in nuclear reactors and how they affect fuel performance is not straightforward. But the practical differences between traditional and TRISO-based fuels would be plainly obvious if we could observe the fuel forms in action. We can't visually observe nuclear accidents as cameras can't survive the radiation, but we can show what happens using animations. So I rigged up a quick animation showing how traditional fuel and TRISO/FCM fuel look like as they encounter the same or similar conditions. I've made simplifications for the sake of comparison and illustration, but the general idea stands that during severe accidents, traditional fuel will fail to the point of melting and vaporization while TRISO/FCM fuel remains solid and functional.